Voltage indicator



June 3o, 1936. w, R.HTER 2,045,801

VOLTAGE INDICATOR Filed June 19, 1935 2 Sheets-Sheet l IUI .IAAAAAAVIVIVVVV AAAAAAAAA VVVVVVVVV Z 5 l INVENTOR.

Walfher Richie? Kam.

' ATTORNEY.

June 30, 1936. w. RICHTER VOLTAGE INDICATOR Filed `Ju'ne 19, l955=IZSheQtS-Shee 2 INVENTOR Walilzer Rz'clzer ATTORNEY.

Patented )une I f n n UNITED STATES .PATENT OFFICE weisheiniehter,wensten, wis.. assuma-to A. 0. Smith Corporation, Milwaukee, Wis., acorporation ot New York Appueeiion .rime 1a, 193s, sei-in No. zam

v5 ieime.- (ci. 1v1-sui The present invention relates to a device forstrume'nt arrangedin accordance with the present indicating voltages andmore specifically-to such invention;

a device Afor indicating direct current arc volt- Figs'. 2 and.3 armodiilcations of the present ages. l invention;

5 The present application ismade a continuation Fig. 4 is a perspectiveview o! a mounting for I in part oi applications Serial No. 728,886,entitled the comparison lamps of Figs. 1 to 3; and' Welding arc voltageindicator, nied June 4, 1934,` Fig. 5 is a perspective view oi' awelding operand Serial No. 729,590, entitled Arc length inators shieldin which the comparison lamps of dicator and filed by the presentapplicant'June Fig. 4 are inounted.

8, 1934. Referring to Figure 1, III represents a welding 1o An object ofthe present invention is theproarc or other direct current voltag to beinvision of a greatly improved device for ampliiyvestigated or otherwiseutilized in t e operation ing direct current voltages or the changesthereof the device ofthe present invention. In the of and moreparticularly the application of said earlier application,- Serial No.729,590, a device l5 device in the indication of direct current arc wasdisclosed by which indications of the value u voltages or arc lengths toa welding loperator. of a direct current voltage, such as that at I il,

A i'urther object is the provision of apparatus were provided throughthe means of a particularly adapted for indicating such arc posedalternating current. 'I'he said A. C. curvoltages or arc lengths to awelding operator in rent was ampledinceordanee with the m88- Such amanner that said operator may be fully nitude of the D. C. voltage atIll. There were also 2o awareoi the voltage condition of his weldingmeans provided t0 eliminate from Such indicaarc without the necessity ofhaving his attention tions the effect of any rapid change oralternadiverted from the observation of other important tion that existsin the voltage under observation. welding conditions. Said ampliied A.C. representation oi the D. C.

A further object of the invention is to provide VOItBge iS brOadlyuseful not only in indicating 25 a device embodying certain principlesdisclosed the value thereof, but in control devices or other in theabove-mentioned applications,v but simapplication in which'thevariations of the D. C.

pimed and improved moreover, Y voltage are to be employed. These andother c Another object oi the present invention is to hienlyedventeseevsfeatures ere retained in the 3 provide a direct current voltageindicating deiieVlceS 0f the Present invention- 30 vice in which theindication is produced by means Referring ngnin t0 Figure 1i eieti'onictube ii of an electronically amplmed superimposed A. C is maderesponsive tothe direct current voltage voltageQsuch device being so asto changes' atarc i. by connections 0m said "c be immune to disturbancesfrom any` alternatt0 grid i2 and cathode n- The uxiiiai'y uni ingcurrent components of the unidirectional directmnal voltages neded t0@erste the elec" u -volg empluyed mr the operation o! the electronic'units or the device disclosed are obtained trmc amplifying umts.from rectifier unit I4 fed from a 110 volt al A runner object oftheinventionis to provide am mi smuce Tm direct' mmm o the Operator, withintherme of his conscious sont vltag f mit '4 is applied acm conduc- 4 mimbignami 1 mmm f its r 'am insiie e eibeienusuy coment potentielbeienmgwiin en intermediate renee with the tween the pieten of tube uand the cathode tolerance of which the absence of indication n a neonglow tube" mm with d'. the existence of predetermined or I.. isconnected across the @umg terminals II 4s seleeilid vii8e and is oftnereetiner. Instead of a neon tube u It is furthef Obiect 0f in#Pmi-mun 'a voltage regulator tube,V y be employed. Any to improve heSeem 0f meeuw dem variations in Aine n.- c. output voltage or the of theelw described and te more Perfectly reeiineiere absorbed in resistanceis. the voli;- nlimlnte ditlll'bnng 0f auch indication by age 4dropthrough tube Il being Substantially changes or variations in Aconditionsextraneous constant. A potentiometer resistance 2l is ap- 50 to thevoltage-being investigated. plied across neon tube I l to provide anappro; Other objects will become apparent by referpriate voltage sourcefor the plate'circuit oi' tube jee-:gte and the attached draw- Il. PlateI1 is then connected to potentiometer wl'igureiisadilgrammauesketchotaninthrcughleriesn.

"-work 23 to which arc cso , produce the biasing with the conductordition, further In the device as illustrated in Figure 1, the

andthe electrode 24 positive. Two voltages are combined in oppositerelationship to provide the biasingv voltage for application betweengrid I2 and"iilament I3. One of these two voltages is the voltage dropacross iixed resistance 25 and the lower part of variable resistance 25.This. voltagei's relatively constant once the adjustable contact 21 `isset to the point on resistance 26 Awhich corresponds in the operation ofthe deviceto the voltage to be maintained across arc I0. The totalvoltage drop across resistances 25, 26, and 29 is substantiallyconstant/as explained before by reason of neon tube I9.

- The other and opposed voltage combining to voltage applied to grid I2is that of the resistance drop in resistance 29. Resistances 29 and 30are two high resistances 3I leading to' grid I2 at-l tachedtherebetween. These resistances are `so related that the resultantvoltage drop across 29' will normally exceed that across resistances 25and 26 to'which it is opposed, thereby providing the negative biasapplied to grid I2. The adjustment of contact 21 provides the means ofsetting and calibrating the apparatus for different desired voltages atl0. A

Condenser 32 is so selected that', placed as it is in 'series with highresistance 3II acrossA the arc and in parallel with resistance time lagfactor isproduced; Said factor is made eifectlve to substantiallyeliminate all rapid fluctuations in voltage appearing at the arc frombeing impressed across grid I2 and cathode I3.

In the device of Figure 1, indications of arc voltage values areconveyedto the welding operator by means of lamps 33 and 34. These lampsare so arranged and associated with the remainder of the'device that onelamp is made to be bright when the voltage at the arc is more than thatdesired or .that to whlch'the contact 21 is set, and that the other lampis made'to be bright when the said voltage is lower than that of ythesetting, 'the iirst lamp having been extinguished. When the arc voltageis within the desired range, -both lamps are without illumination. v

Thisarrangement o the lamp operation is particularly advantageous to theoperator who has the lamps within his range oi vision as in the weldinghood 35 of Fig. 5. These lamps 33 and 34 are also shown in theirmounting case 3B of Fig. 4 which case is mounted on hood 35. Thus theoperator needs only to 'be aware that light exists in one source of theother or not at all to be immediately informed of what correction tomake in the handling of his arc. The lamps also dim gradually as the arcreaches its desired coninforming the operator of the urgency or lack ofurgency of correction for his welding arc.

The results above described as embodied in the. indicating lamps of thepresent device and particularly in Figure 1 are secured as follows.

A small alternating voltage is impressed upon the cathode grid circuitrof tube It by means oi transformer 31 through condenser 32. Condenser3B is inserted to act as a voltage divider and give the desired A. C.voltage across condenser 32 which condenser has been previously selectedto ass/ist in damping out the uctuations of arc voltage as applied tothis same grid circuit.

As explained in the earlier application, the

III is sprung is negative 29, a Asuitable A'former' 44. Fluctuationsv incathode voltage due scribed. As before, lamps 33 pling resistance 58direct current bias of this tube eiectively controls the degree ofampliilcation of the A. C. voltage impressed thereon. These' A. C;components are successively amplied rst in tube 39 and then in powertube 40, the couplings from tube to tube being such that only thealternating oomponents are amplied. The resultant amplified alternatingcurrentcomponent appears on the secondary side 4I of transformer 42where it is upomthe lamps 33 and 34 in series. When no A. C. amplicationtakes place there is no current supplied through secondary 4I.

- This is in the present case the condition of an arc voltage above thedesired voltage. At this time, lamp 34 is made bright by a relativelyfixed 1 current received from transformer y31 through resistance 43.Lamp 33 is prevented from receiving such current by the inductance andequivalent resistance of transformer 42 in combination with tube 40. y

As the arc voltage drops, amplied A. C. currents appear at 4I and iiowthrough lamps '33 and 34 in opposite phase to the currentrst flowing in'lamp 34. A lowering of the arc voltage dims the light of lamp 34 by theresulting diminution of the current ilowing therethrough and becomesnon-luminous within the desired selected at resistance 26 by contact 21.

The cathode of power tube 40 and the heaters of tubes II and 39 aresupplied by heater transto said A. C. connections are prevented by theemployment of an ecient lter'condenser 45. The direct current Vsuppliedby rectifier Mis also made steady by theA employment of an effectivelter condenser 46.

In Fig. 2, certain modiilcations are made in the mode of reaching thesignal combination justy deand 34 are caused to respond to voltagechanges. However, trans'- former 42 is in this case center tapped on itsprmary with said tap connected to one secondary terminal I5 of rectierI4, the extremities of said primary winding of the transformer beingconl nected respectively to the plates of two push-pull power tubes 41and 48 arranged to supply said transformer, and the cathodes of tubes 41and 48- being connected to the other side I6 of the rectier throughplate current control resistance 49.'

Bythe above arrangement of ythe power tubes, all necessity for lteringout of A. C. components from the D. C. of rectifier I4 at these tubes isremoved since any such component would ow into transformer at the centertap and neutralize itself by flowing in equal and opposite pathstherethrough. lIt will be noted all such filtering has been eliminated.

In Fig. 2, the push-pull tubes 41 and 48 are controlled by grids and 5Isubjectedto alternating voltage values obtained from sections 52 and 53of duplex tube 54. The plate currents for tube 54 are obtained throughresistance 5E and the supply voltage is filtered of A. C. components bymeans of a lter condenser 56. This lter condenser is a very smallinexpensive condenser compared to those required in Figure 1 for theoutput of the rectier. Tube section 52 receives andampliiies theimpressed A. C. voltage in a manner similar to the tube I I of Fig. l.Grid 51 of tube section 53 receives its voltage from couwhich ties it togrid. 5E.

The 75 filtering 7 mim: of tube section s: is then coupled to the gridli of the push-pull tube 48, which in turn controls the output of thetube 48. The connection of grid 5'! to resistance 5B is so adjusted asto produce equal magnitudes oi' A. C. output in each of the push-pullcircuits. These outputs are seen to be 180 apart in phase and, sincethey are connected as shown to transformer 42, they combine to supplyalternating current in unison to this transformer and produce in thesecondary thereof the current employed to control the illumination ofthe indicating lamps 33 and 34.

Thetubes 41 and 48 are in effect two power tubes which both feed thesignal lamp circuit, but are so used that any alternating currenteil'ects vother than the one originally supplied by the output of tubesection 52 are neutralized. Filtering oi' the unidirectional voltagesupplied to the power tubes by the rectifier is made unnecessary.

In Fig. 3,'the arrangement of Fig. 2 is modified by employing tubes 69and 60 to amplify the impressed alternating current values. The platecurrent alternatingkvalue of tube 60 is then applied to transformer Ilof which the secondary is center tapped with said tap connected to onepolarity, the two ends of said secondary being employed to produce the.grid voltages of the two push-pull power tubes 82 and 63,. 'I'hus theselatter tubes, as in Fig. 2, feed transformer 42 with an alternatingcurrent which is an indication of the voltage in are III.

The devices of the present invention may be used to indicate othercharacteristics of a welding are as for instance the current values insaid arc by passing such currents through a shunt and applying theresulting voltage across such shunt to the tube circuits to control theamplication of the A. C. imposed upon such tube. These devices may alsobe used to indicate other voltages and be used in various electricaldevices. It will be clear also that the currents produced by the devicesfor indicating certain electrical values could also be employed toregulate or control such values as well as to operate indicating means.

I claim:

1. A device for indicating to an` arc welding operator the voltage ofhis welding arc comprising a pair of light sources mounted within therange of vision of said operator, and means responsive to the arcvoltageto cause one of said lights to increase in illumination fromnone'as the arc voltage increases above a given selected voltage rangeand the .other light toA increase in illumination from none as thecreases below said selected voltage range.

2. A device arranged to indicate electrical voltages comprising meanstoindicate when such,

voltage value is above a given predetermined range ot values, and othermeans to indicate when said voltage is below said range.' said two abovevelectronic tube said .nrst source, a

are voltage de-L `first source falls below ther i'rom said predeterminedrange toward the 5 high and low values.

3. An indicator for a'voltage characteristic of a unidirectionalelectric current comprising an ci' at least vthree electrodes. a sourceof alternating voltage oi' predetermined 1 value, means connecting saidalternating voltage and said unidirectional electric current circuit tosaid tube to produce an alternating voltage varying invalue-inaccordance with the variations in said characteristic of theunidirectional current, 15 and means to apply an ampliied value of saidvarying alternating voltage to a pair of indicating lights and to applyto one of said lights an additional voltage of a phase substantiallyopposed to said last named varying alternating voltage to cause one lampto be bright when the unidirectional current characteristic is above aselected value and the other light to be bright when said characteristicis below said selected value.

4. In a device responsive to the voltage of a 25 unidirectional electriccurrent, the combination comprising a thermionic tube of at least threeelectrodes, means for impressing across two of such electrodes analternating voltage of .prede, termined voltage to produce ampliedaltemat- 30 ing values of said alternating voltage, means to vary theamplitudes of said alternating values in accordance with variations inthe said unidirectonal voltage, amplifying means including an electronicpush-pull ampliiler responsive to said am- 35 in accordance with acharacteristic to be indicated,

two voltage responsive devices, means connecting Said devices in serieswith each other and with4 second source' of voltage of predeterminedvalue, means connecting said second source across lthe terminals oi oneof said devices to oppose the voltage applied to said device by saidfiirst source, whereby/said last mentioned device will be operated bythe voltage from said second source when the voltage from said A apredetermined value and said other device will be operated by the volt-58e from said rst source when the latter rises above a predeterminedvalue. I f

WALTHER RICHTER, 60

